1,721,042 research outputs found
The link between narcolepsy and autonomic cardiovascular dysfunction: a translational perspective.
No full textNarcolepsy is a rare disease that entails excessive daytime sleepiness, often associated with sudden episodes of muscle weakness known as cataplexy. Narcolepsy with cataplexy (NC) is due to the loss of hypothalamic neurons that release the neuropeptides orexin A and B. Orexin neuron projections prominently target brain structures involved in wake-sleep state switching and the central autonomic network. This review provides an updated summary of the links between NC and autonomic cardiovascular dysfunction from a translational perspective. The available evidence suggests that, compared with control subjects, the heart rate in patients and animal models with NC is variable during wakefulness and normal to high during sleep. Responses of the heart rate to internal stimuli (arousal from sleep, leg movements during sleep, defense response) are blunted. These alterations result from orexin deficiency and, at least during wakefulness before sleep, involve decreased parasympathetic modulation of the heart rate. On the other hand, NC in patients and animal models is associated with a blunted fall in arterial blood pressure from wakefulness to sleep, and particularly to the REM state, coupled to a variable decrease in arterial blood pressure during wakefulness. The former effect is caused, at least in part, by deranged control of the heart, whereas the latter may be due to decreased vasoconstrictor sympathetic activity. Systematic studies are warranted to help clarify whether and how the links between NC and autonomic dysfunction impact on the cardiovascular risk of patients with narcolepsy
Browning of Adipocytes: A Potential Therapeutic Approach to Obesity
No full textThe increasing prevalence of overweight and obesity suggests that current strategies based on diet, exercise, and pharmacological knowledge are not sufficient to tackle this epidemic. Obesity results from a high caloric intake and energy storage, the latter by white adipose tissue (WAT), and when neither are counterbalanced by an equally high energy expenditure. As a matter of fact, current research is focused on developing new strategies to increase energy expenditure. Against this background, brown adipose tissue (BAT), whose importance has recently been re-evaluated via the use of modern positron emission techniques (PET), is receiving a great deal of attention from research institutions worldwide, as its main function is to dissipate energy in the form of heat via a process called thermogenesis. A substantial reduction in BAT occurs during normal growth in humans and hence it is not easily exploitable. In recent years, scientific research has made great strides and investigated strategies that focus on expanding BAT and activating the existing BAT. The present review summarizes current knowledge about the various molecules that can be used to promote white-to-brown adipose tissue conversion and energy expenditure in order to assess the potential role of thermogenic nutraceuticals. This includes tools that could represent, in the future, a valid weapon against the obesity epidemic
Fisiologia gastrointestinale
No full textQuesto volume fornisce una presentazione precisa, aggiornata e integrata dei vari aspetti della fisiologia gastrointestinale. In tutti i capitoli sono presenti richiami ad aspetti clinici, in particolare negli inserti Considerazioni cliniche e fisiopatologiche, e Approfondimenti dedicati ad argomenti specifici. L’iconografia ampia e dettagliata facilita anche visivamente l’apprendimento dei concetti discussi nel testo
Improving Sleep to Improve Stress Resilience
Get PDFPurpose of Review: The neuroendocrine stress response is a natural process of our body which, however, might become toxic if not properly turned on and off. Resilience is the ability to adapt to adverse situations and, particularly, to cope with uncontrolled stress. Resilience and stress are two opposite faces of the same coin, and both are deeply linked to sleep: low resilience means higher stress and, through that, more sleep disorders. The aim of the present paper is to review the complex relationship between these actors and to highlight the possible positive role of good sleep in contrasting chronic stress situations. Recent Findings: Promotion of cognitive-behavioral therapy for insomnia patients improves sleep quality and, through that, produces lower general stress, lower depressive symptom severity, and better global health. Summary: Sleep is a modifiable behavior and, according to recent studies, its improvement might enhance resilience and, in turn, reduce stress
Role of the orexin system in the bidirectional relation between sleep and epilepsy: New chances for patients with epilepsy by the antagonism to orexin receptors?
Get PDFEpilepsy is a common neurological disorder, affecting patients of all ages, reducing the quality of life, and associated with several comorbidities. Sleep impairment is a frequent condition in patients with epilepsy (PWE), and the relation between sleep and epilepsy has been considered bidirectional, as one can significantly influence the other, and vice versa. The orexin system was described more than 20 years ago and is implicated in several neurobiological functions other than in controlling the sleep–wake cycle. Considering the relation between epilepsy and sleep, and the significant contribution of the orexin system in regulating the sleep–wake cycle, it is conceivable that the orexin system may be affected in PWE. Preclinical studies investigated the impact of the orexin system on epileptogenesis and the effect of orexin antagonism on seizures in animal models. Conversely, clinical studies are few and propose heterogeneous results also considering the different methodological approaches to orexin levels quantification (cerebrospinal-fluid or blood samples). Because orexin system activity can be modulated by sleep, and considering the sleep impairment documented in PWE, the recently approved dual orexin receptor antagonists (DORAs) have been suggested for treating sleep impairment and insomnia in PWE. Accordingly, sleep improvement can be a therapeutic strategy for reducing seizures and better managing epilepsy. The present review analyzes the preclinical and clinical evidence linking the orexin system to epilepsy, and hypothesizes a model in which the antagonism to the orexin system by DORAs can improve epilepsy by both a direct and a sleep-mediated (indirect) effect
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Netter's Fisiologia. L'essenziale
No full textLa fisiologia umana è lo studio delle funzioni del corpo a tutti i livelli: l’organismo nel suo complesso, gli apparati, gli organi, i tessuti, le cellule e i processi fisici e chimici.
La fisiologia è una scienza complessa, che contiene al suo interno concetti e principi di biologia, chimica, biochimica e fisica. Spesso per capire completamente i concetti fisiologici, è necessario affrontarli con modalità didattiche diverse, che vanno oltre i testi standard o le classiche lezioni universitarie. Questa seconda edizione di Netter’s Fisiologia – L’essenziale è stata preparata partendo da tale presupposto. Le molte illustrazioni e il testo conciso e ricco di elenchi puntati e ausili grafici servono per coinvolgere gli studenti e focalizzare la loro attenzione sulla comprensione degli aspetti essenziali dei concetti, in particolare quelli più difficili. Non è un manuale dettagliato, ma una guida per apprendere ciò che è essenziale, assieme al lavoro in classe e ad altre risorse, se necessarie.
L’organizzazione segue il classico ordine con cui si insegnano le sottodiscipline della fisiologia. Inizia con i compartimenti fluidi, i meccanismi di trasporto e la fisiologia cellulare, poi continua con la neurofisiologia, la fisiologia cardiovascolare, l’apparato respiratorio, la fisiologia renale, l’apparato gastrointestinale e l’endocrinologia. È un testo ideale per chi ha memoria visiva. Tutto il libro è illustrato con i bellissimi disegni del compianto Frank Netter e con le altrettanto belle e più recenti illustrazioni di Carlos Machado, John Craig, James Perkins e Tiffany DaVanzo
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